[SPARK-18835][SQL] Don't expose Guava types in the JavaTypeInference API.

This avoids issues during maven tests because of shading.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #16260 from vanzin/SPARK-18835.

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/JavaTypeInference.scala

@@ -19,6 +19,7 @@ package org.apache.spark.sql.catalyst
 
 import java.beans.{Introspector, PropertyDescriptor}
 import java.lang.{Iterable => JIterable}
+import java.lang.reflect.Type
 import java.util.{Iterator => JIterator, List => JList, Map => JMap}
 
 import scala.language.existentials
@@ -54,12 +55,21 @@ object JavaTypeInference {
     inferDataType(TypeToken.of(beanClass))
   }
 
+  /**
+   * Infers the corresponding SQL data type of a Java type.
+   * @param beanType Java type
+   * @return (SQL data type, nullable)
+   */
+  private[sql] def inferDataType(beanType: Type): (DataType, Boolean) = {
+    inferDataType(TypeToken.of(beanType))
+  }
+
   /**
    * Infers the corresponding SQL data type of a Java type.
    * @param typeToken Java type
    * @return (SQL data type, nullable)
    */
-  private[sql] def inferDataType(typeToken: TypeToken[_]): (DataType, Boolean) = {
+  private def inferDataType(typeToken: TypeToken[_]): (DataType, Boolean) = {
     typeToken.getRawType match {
       case c: Class[_] if c.isAnnotationPresent(classOf[SQLUserDefinedType]) =>
         (c.getAnnotation(classOf[SQLUserDefinedType]).udt().newInstance(), true)

sql/core/src/main/scala/org/apache/spark/sql/UDFRegistration.scala

@@ -23,8 +23,6 @@ import java.lang.reflect.{ParameterizedType, Type}
 import scala.reflect.runtime.universe.TypeTag
 import scala.util.Try
 
-import com.google.common.reflect.TypeToken
-
 import org.apache.spark.annotation.InterfaceStability
 import org.apache.spark.internal.Logging
 import org.apache.spark.sql.api.java._
@@ -446,7 +444,7 @@ class UDFRegistration private[sql] (functionRegistry: FunctionRegistry) extends
           val udfReturnType = udfInterfaces(0).getActualTypeArguments.last
           var returnType = returnDataType
           if (returnType == null) {
-            returnType = JavaTypeInference.inferDataType(TypeToken.of(udfReturnType))._1
+            returnType = JavaTypeInference.inferDataType(udfReturnType)._1
           }
 
           udfInterfaces(0).getActualTypeArguments.length match {